From the options in your list, i'll go for the 4th -Dad/Mum. But that which is most painful to loose is one's twin brother/sister. Most especially when he/she is your identical twin. Identical twins shares same love for themselves. They are ready to risk their lives and even die for the safety of the other.Their souls melts for each other.

Marvisdby: From the options in your list, i'll go for the 4th -Dad/Mum. But that which is most painful to loose is one's twin brother/sister. Most especially when he/she is your identical twin. Identical twins shares same love for themselves. They are ready to risk their lives and even die for the safety of the other.Their souls melts for each other.